1. Field of the Invention
The present invention relates generally to the field of snorkels used for diving and more specifically to a multi-tubular diving snorkel having generally parallel elongated tubes to substantially prevent the mixture of intake air and exhaust air to avoid a respiratory efficiency reduction that would otherwise occur when intake air and exhaust air are mixed in a conventional snorkel tube.
2. Prior Art
The prior art closest to the present invention of which the applicants are aware is disclosed in U.S. Pat. No. 5,117,817 to Lin and is entitled, Vertical Co-axial Multi-tubular Diving Snorkel. This patent is directed to a multi-tubular diving snorkel in which coaxial outer and inner tubes provide substantially separated exhale and inhale channels. Like the present invention, this device attempts to use valves in order to assure that intake air enters only one of the two channels and exhaust air enters only the other of the two channels. There are however, at least two significant disadvantages of this prior art device. The most significant is the fact that the inner tube is terminated well before the mouthpiece of the snorkel, adjacent the bottom end thereof, resulting in a significant mixture of intake and exhaust air at the lower end of the snorkel, despite the separated tube structure thereof. Consequently, despite the attempts to provide separate channels where intake air flows through only one such channel and exhaust air flows through only the other such channel, because the inner coaxial channel does not extend the full length of the snorkel, there is a significant reduction in the efficiency of separating the dirty air from the clean air, thus partially defeating the advantage of having two separate channels.
Another significant disadvantage of the aforementioned prior art arises from an inherent difficulty in the geometry of such a snorkel in which separate tubes are coaxial or concentric. More specifically, because of the inherent nature of coaxial tubes, the outer tube must have a significantly larger diameter than the inner tube and because the inner tube must have a sufficiently large diameter to provide an unimpeded exhale channel, the outer tube must have a larger diameter than that normally desired in a snorkel tube.
It would thus be highly advantageous to provide a multi-tubular diving snorkel which has the advantages of the aforementioned prior art, namely significant separation between dirty and clean air, the former being exhaled air and the latter being intake air but, while at the same time, overcoming the aforementioned disadvantages of such prior art. More specifically, it would be desirable to have a multi-tubular diving snorkel in which the separation of intake and exhaust air is more significant and efficient and in which the relative cross-section of the separated tubes are independent of one another and thus may be controlled without concern of how one affects the other as is inherent in the aforementioned prior art.